CHEM 101DL Study Guide - Midterm Guide: Rate Equation, Slow Step, Joule
26 Jun 2018
School
Department
Course
Professor
Name ________________________ June 21, 2018
Chemistry 101DL Dr. T. Woerner
General Chemistry
Exam #2
Please Note:
a) In order to obtain credit for the correct numerical answer in problems involving calculation it
is necessary to show all work and the reasoning process in detail. In all cases the final numerical
answer is worth one point.
b) If in doubt as to the extent of explanation required in any given question put in more than
what you believe to be the minimum. Use the back of the page when you need more room.
c) This is a 2.5 hour, open book, open notes, closed mouth, closed internet examination.
e) The gas constant R can be expressed as
!"#$% &$'() *+
,-./0
; or, 0.0821
f) There are 7 questions for a total of 65 points. There is also one 5-point extra credit problem.
……………………………………………………………………………………
1)(12 pts)
a) Consider the following two compounds: a) acetic acid (C2H4O2); and, b) ethanol (C2H6O).
We have written their Lewis structures on the board, and on paper, many times in the past weeks.
I am hopeful that you are familiar with them. However, if you are at all unsure, I am confident
that you can refresh your memory either from your notes or from the text.
Draw Lewis structures for both acetic acid; and, ethanol. Describe the bonding: What is the
hybridization on each carbon and oxygen? As well, describe both the electronic, and molecular
geometry around the carbon and oxygen atoms. Which bonds are sigma and which (if any) are
pi? If there are pi bonds in your structure(s), draw pictures of the pi-bonding arrangement of
orbitals so that you clearly demonstrate your understanding of this bonding configuration.
⋅Atm
K⋅mole
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b) It is found experimentally that the acid ionization constant of acetic acid is
123 $"! & $'45
,
while that of ethanol is
123 $"67 &$'489"
Write balanced chemical equations to describe these
ionizations reactions. Referring back to your structures from part a) of this question, explain
why the ionization constant for acetic acid is so much larger (ca.
$'88:
times larger!) than
ethanol. That is, why is acetic acid considered an acid, while ethanol is not? Use the back of
the page for your answer.
2)(12 pts) In 2016, approximately 9.8 million tons of ammonia were produced in the United
States. As part of the manufacturing process, the chief source of hydrogen gas is this reaction for
the reforming of methane at elevated temperatures:
CH4(g) + 2H2O(g) CO2(g) + 4H2(g)
The following data are available:
A) CO(g) + H2O(g) CO2(g) + H2(g) ∆H = 40 kJ; Kc = 3.6 at 831 K
B) CO(g) + 3H2(g) H2O(g) + CH4(g) ∆H = 230 kJ; Kc = 5.30X104 at 831 K
a) Use these data to determine the values of ∆H and Kc for the reaction of CH4(g) with H2O(g) to
produce H2(g) and CO2(g) at 831 K.
b) Determine the value of Kp for this same reaction at 831 K.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Please note: in order to obtain credit for the correct numerical answer in problems involving calculation it is necessary to show all work and the reasoning process in detail. In all cases the final numerical answer is worth one point: if in doubt as to the extent of explanation required in any given question put in more than what you believe to be the minimum. Use the back of the page when you need more room: this is a 2. 5 hour, open book, open notes, closed mouth, closed internet examination, the gas constant r can be expressed as 8. 314 10() K mole: there are 7 questions for a total of 65 points. There is also one 5-point extra credit problem. 1)(12 pts: consider the following two compounds: a) acetic acid (c2h4o2); and, b) ethanol (c2h6o). We have written their lewis structures on the board, and on paper, many times in the past weeks.
